\begin{table}[htbp]\centering
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\caption{P-values for test of equal time trends by subgroup}
\begin{tabular*}{\hsize}{@{\hskip\tabcolsep\extracolsep\fill}l*{4}{c}}
\toprule
            &    US (GSS)         &    US (HRS)         &          UK         &     Germany         \\
            &                     &                     &                     &                     \\
\midrule
Temporary vs. permanent workers&                     &                     &        0.01\sym{**} &        0.03\sym{*}  \\
\addlinespace
Parttime vs. fulltime workers&        0.45         &        0.46         &        0.45         &        0.99         \\
\addlinespace
New starters vs. incumbent workers&                     &                     &        0.07         &        0.70         \\
\addlinespace
Male vs. female&        0.38         &        0.81         &        0.61         &        0.45         \\
\addlinespace
Over-50s vs. 25-49 vs. under-25s&        0.56         &                     &        0.00\sym{***}&        0.39         \\
\addlinespace
Tertiary degree holders vs. no degree&        0.27         &        0.49         &        0.04\sym{*}  &        0.02\sym{*}  \\
\addlinespace
Marginally- vs. non-marginally employed&                     &                     &                     &        0.59         \\
\midrule
N           &          21         &          12         &          27         &          34         \\
\tabnotes{5}{This table displays the p-value for an F test that the time trends for the two subgroups in question are equal. *\textit{p} < 0.05, **\textit{p} < 0.01, ***\textit{p} < 0.001}
